login
A157582
Half the number of length n integer sequences with sum zero and sum of squares 5000.
1
1, 3, 222, 23430, 2211435, 165640041, 11463980983, 700674124347, 41384377023300, 2326405435793384, 127560765651968055, 6827700441824422953, 350130844722624976920, 17081201454932094454170, 796830250007891403178002
OFFSET
2,2
LINKS
FORMULA
[cache enabling] count(n,s,ss)->count(n,t,tt) where t=s mod n, q=(t-s)/n, tt=ss+2*q*s+n*q^2; count(n,t,tt)=sum[i^2<=tt]{ count(n-1,t-i,tt-i^2) }. a(n)=count(n,0,5000)/2.
CROSSREFS
Sequence in context: A071881 A157557 A279532 * A241098 A254157 A131493
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 02 2009
STATUS
approved